Non-removably mounted particulate and gaseous filter media have been housed in more or less conventional permanent frame constructions for many, many years. Such frames generally consist of metal channel members forming the four sides of a rectangular configuration with the edges of the filter media being disposed within the channels. Typically the side walls of the channel members are bent inwardly to firmly engage and fix the outer edges of a layer of filter media in position within the frame.
While this is generally a satisfactory construction for particulate filter media of relatively long life or which can be cleaned and re-used, it represents a considerable expense in those applications wherein the filter media is relatively short-lived. In such situations, a disposable and replaceable media is desirable.
In applications wherein a combination of particulate and gaseous filter media are required, it is not unusual for one or more types of such media to be relatively shortlived. In this situation, a less expensive disposable filter media held by an inexpensive throwaway frame construction is desirable.
However, most prior frame constructions of the stronger permanent type do not readily permit removal and replacement of layers of filter media held therein and the less expensive disposable frame constructions are less sturdy, weak and otherwise not satisfactory for certain applications. This type of prior art incorporated all filter media within a singular frame which must be thrown away when one or more of the filter media has served its useful life or to employ a separate filter frame for each type of media used.
Other prior art filter assemblies such as that in U.S. Pat. No. 4,737,147 utilized a plurality of clips to removably retain layers of filter media, but the clips had an awkward shape that was complex to manufacture and whose installation was less than simple. The clips also could not readily accept and accommodate multiple layers of removable filter media.
It is an object of the present invention to provide a filter assembly having one or more disposable layers of filter media removably retained within a filter frame by a plurality of elongated clips that are easily manufactured and installed.